Quality of Service (QoS) is the concept that transmission rates, error rates, and other network transmission characteristics can be measured, improved, and to some extent guaranteed in advance of a network transmission. QoS is a significant concern for high bandwidth networks that regularly transmit large amounts of data such as video, audio, multimedia, and the like. Moreover, QoS is problematic for geographically dispersed networks, such as the Internet, where any single network transaction can span multiple sub-networks through multiple Internet Service Providers (ISPs).
Attempts to provide decent QoS architectures often suffer from scalability issues. That is, independent sub-networks (e.g., ISPs) are required to be too heavily dependent upon one another to produce any viable commercial solution. As soon as independent sub-networks become dependent upon the operational specifics of other sub-networks, they become less scalable and less desirable. When scalability is adequately achieved, the result is usually achieved with overly complex implementation schemes that dramatically decrease network throughput at the expense of providing scalability.
Accordingly a more scalable QoS technique for large geographically disperse networks is needed, where scalability is achieved in a manner that does not significantly impact network throughput and is not overly complex.